METRE RULER, RETORT STAND, HOOKE'S LAW

METRE RULER

length of ruler: 	100cm or 1000mm

			distance from weight to fulcrum		mass
no mass: 		500mm 					0g
50 grams: 		290mm 					50g
100 grams: 		210mm					100g
150 grams: 		160mm 					150g
200 grams: 		130mm					200g
250 grams:		114mm					250g
300 grams:		100mm					300g
350 grams:		90mm					350g

mass of ruler:

			let mass of ruler be M

for 50 grams:		(500 - 290)M = 290 * 50
			210M = 14500
			M = 69.05g
for 100 grams:		(500-210)M = 210 * 100
			290M = 10500
			M = 72.41g
...

actual mass of ruler (from balance):		67 grams


RETORT STAND

length of retort stand:	77cm or 770mm

			distance from weight to fulcrum		mass
no mass:		690mm					0g

200 grams:		615mm					200g

mass of retort stand:

			let mass of retort stand be M

for 200 grams:		[(770-615)-(770-690)]M = 615 * 200
			75M = 123000
			M = 1640g

actual mass of retort stand (from balance):	1609 grams (if I remember correctly)


HOOKE'S LAW

		mass	force	position	extension
0 grams		0.00kg	0.0N	0.475m		0.000m
50 grams	0.05kg	0.5N	0.420m		0.055m
100 grams	0.10kg	1.0N	0.365m		0.110m
150 grams	0.15kg	1.5N	0.310m		0.165m
200 grams	0.20kg	2.0N	0.255m		0.220m

force constant (k):

for 50 grams:		0.5 = k * 0.055
			k = ~9.09
for 100 grams:		1.0 = k * 0.110
			k = ~9.09
...

actual force constant (from these calculations):	~9.09